This invention relates to a mechanism for controlling vapor fuel generated in the float chamber of a carburetor.
In the conventional vaporized fuel controllers, the gas chamber of the float chamber becomes connected to the inner vent or the charcoal canister by changing over a valve, which is actuated either by (1) the negative pressure in the intake manifold only or by (2) the intake manifold negative pressure combined with some mechanical interlocking means or with an electromagnet. However, with the first method (1), reduction in the negative pressure caused while the engine is running at high speeds closes the passage leading to the inner vent and opens the passage to the canister, thus connecting the gas chamber to the canister and wasting the vapor fuel. As a countermeasure to the first method, the second method (2) has been proposed to change over the valve. However, this method has a disadvantage that the mechanical interlocking means becomes very complicated.